Parts for a conventional single focus lens module for digital camera from the object side to the image side are (1) photo taking lens which includes a mechanical shutter; (2) lens holder assembly which includes focus adjusting mechanism; (3) electronic photo taking assembly wherein the light sensor can be CCD or CMOS. The mechanical shutter is activated by mechanical interaction and electronic transferring action with the circuit board, so that the orientation of the shutter has to be set and cannot be rotated about the optical axis of the lens. In order to make the images formed on the light sensor and obtain a better quality image, a focus adjusting mechanism that is able to move linearly is connected to the lens holder so as to prevent the photo taking lens from rotating. Nevertheless, there are shortcomings as follows:                1. In order to allow the lens to move back and forth, gaps exist between parts of the focus adjusting mechanism. Tolerances are accumulated between the parts between the photo taking lens and the light sensor. The number of the parts is increased, the accumulated tolerances are severe so that the optical axis is not perpendicular to the light sensor and the image tilts.        2. Mechanical shutter body is located in the photo taking lens so that the photo taking lens has to be assembled from two sides of the shutter. This makes the optical axis be slightly different and the quality of the image is reduced.        3. Mechanical shutter body is located in the photo taking lens and is activated by an actuator. In order not to interrupt the actuator and the focus adjusting mechanism, the actuator is arranged in front of the aperture stop and this arrangement makes the whole lens module to be too thick.        